1. Field of the Invention
This invention relates, in general, to electrical apparatus and, more specifically, to tap-changers for power transformers.
2. Description of the Prior Art
Non-load tap-changers are often used on distribution transformers to permit different voltage ratings of the transformer windings. Various tap-changer arrangements have been used according to the prior art. Depending upon the particular prior art arrangement, each tap-changer has been characterized as having one or more disadvantages over another tap-changer. Electrical and mechanical performance, economy of construction, size, etc. are all factors which determine the overall usefulness of a particular non-load tap-charger.
Particular emphasis has been placed on the simplicity of construction for reasons of economy and reliability. In addition, the expected life of the moving or conducting parts of the tap-changer is very important and of prime concern in the designing of a suitable tap-changer. The ability to provide enough contact pressure without excessive force being required when changing the tap position is also an important objective. Therefore, it is desirable, and it is an object of this invention, to provide an economical non-load tap-changer which has highly desirable mechanical and electrical characteristics.